Both mowers are well-used but not abused.They run and cut grass just fine, have been maintained, have good seats and tires. The smaller LT4000 has the Briggs 14.5 HP Industrial/Commercial Gold engine, 42" cut, 6 speed, handles well, has new oil and battery.The bigger GT6000 Diehard has the 18 HP Kohler Magnum Twin, has plenty of power, 44" cut, Hydro/Automatic tranny and fresh oil. $325 each